[greyhawk50]

Welcome to the Marlin Forum.
Someone with a better understanding of the new 336s should chime in shortly. My 336 is a pre-safety model.
I give you credit for reading the entire manual. Something that I seldom do. I generally skip the basics and read the high points. Not saying that I know everything, obviously I don't, but I've owned firearms for 55+ years and most were used and came without the manual.
I was taught as a youngster to never dry fire a weapon. Some say it is OK with today's guns but I can't bring myself to intentionally dry fire. Safety or no safety, I lower the hammer on my 336 slowly by restricting the travel with my thumb on the hammer, whether for empty storage or loaded safe carry.

 

[greyhawk50]

Greyhawk 50, I'm with you, I'm in my 60's and my dad would get out of his grave and kick my tail all over the world for intentionally dry firing ANY gun.
On the other hand what is a safety for if it is not to prevent a firing sequence to complete!
If I have a safety engaged, and the trigger is pulled, absolutely NOTHING should happen!

When I was just a lad, my first rifle was a Daisy Pump BB Gun. While firing it one day, it ran empty w/o my knowledge. I pulled the trigger and the firing pin came flying out the end of the barrel. Dad was able to replace it but the downtime was unpleasant.
Just recently, I acquired a 20 ga. O/U w/o a selector switch. Not knowing which barrel fired first (and being a little short on smarts that day), with the action open, I placed my index finger over the firing pins and pulled the trigger. It took 3 weeks for the blood blister to dissolve. Not to mention the sting. That much force moving forward w/o anything to stop it has the potential to break the firing pin.
Dropping the hammer on a cross bar safety or even a slide block safety (as with the de-cock lever on a pistol) should be less harmful but it's still metal on metal contact with a great deal of force.
I know what they claim to be OK. To each their own. But just my opinion, I don't think Snap Caps are made just for older guns. and we don't have a reputable gun smith in my area.